The present invention relates to a high-frequency treatment tool which can be inserted into a body to grip tissue and coagulate/incise it.
Generally, as a high-frequency treatment tool capable of gripping vital tissue and coagulating/incising it, a bipolar forceps having jaws as a pair of gripping members for gripping vital tissue and high-frequency current supply electrodes formed on the jaws is known. In this bipolar forceps, when vital tissue to be treated is gripped between the pair of jaws, and a high-frequency current is provided across the electrodes of the jaws, the vital tissue between the jaws is coagulated or incised.
Bipolar forceps of this type are normally used for various purposes, e.g., to stop bleeding from blood vessels included in vital tissue, cauterize a morbid portion or bleeding point on the surface of vital tissue, or close a uterine tube for contraception, and disclosed in, e.g., Jpn. Pat. Appln. KOKAI Publication No. 8-317936, Ger. Publication DE 4138116 A1, Ger. Publication DE 4032471 C2, or EP 0598348 A1.
In the conventional bipolar forceps, especially, when thin membranous tissue is gripped by the jaws, the metal portions of the jaws may come into contact with each other to flow a high-frequency current across the metal portions in contact. That is, the jaws electrically short-circuit. In this case, the high-frequency current does not flow to the tissue gripped between the jaws, so the tissue cannot be reliably coagulated or incised. In addition, if complete coagulation cannot be performed, bleeding may occur during the subsequent incision.
In the bipolar forceps disclosed DE 4138116 A1 or DE 4032471 C2, tissue is gripped by three rod electrodes. For this reason, the tissue escapes upon gripping and cannot be reliably gripped. Hence, coagulation/incision cannot be satisfactorily performed.
In the bipolar forceps disclosed in DE 4032471 C2 (FIG. 2) or DE 4138116 A1 (FIGS. 5 and 6), the far ends of the coagulation and incision electrodes are at the same position to incise the entire coagulation region. This may cause bleeding. In addition, a bipolar high-frequency incision tool disclosed in EP 059348 A1 incises the entire gripped region.